This invention relates to aerosol spray dispensers, and in particular to aerosol spray orifice structures.
Most aerosol dispensers use a fluorocarbon to propel the material to be dispensed. However, fluorocarbons are relatively expensive. In order to reduce the propellant cost, other gases such as carbon dioxide have been proposed as propellants for aerosol dispensers. However, when using gases such as carbon dioxide, the pressure within the aerosol dispenser varies over a much wider range than does the pressure within a dispenser when a fluorocarbon is used. When the aerosol dispenser is first being used, the pressure is high, but it drops to a very low level near the end of use. For example, an initial pressure as high as 85 pounds per square inch (hereinafter abbreviated "psi") may decrease to a level of about 20-25 psi as the last portion of the material being dispensed exits from the aerosol dispenser.
The aerosol valve tips of the prior art generally only operate efficiently in relatively narrow pressure ranges, e.g., from an initial pressure of from about 50 psi to a final pressure of about 20 psi. Furthermore, the aerosol tips of the prior art commonly produce a less efficient or coarser spray than desirable even at high pressure. In general, a finer mist is achieved when the diameter of the exit orifice is reduced, but the minimum size of the exit orifice is limited by molding and assembly considerations.
It would therefore be highly desirable to have a nozzle or an aerosol tip which would operate over a wide pressure range and produce a fine and efficient mist without having an undesirably small exit orifice. The advantages have been realized in the aerosol tip and insert of the present invention.